1. Field of the Invention
The present invention relates to an image forming apparatus more specifically to an image forming apparatus provided with double-side copying and overcopying functions in which copied paper is fed once into a paper stacking unit before being fed again.
2. Description of the Prior Art
Recently, there have been developed electronic copying machines such that two different images can be copied on one (overcopy) or both sides (double-side copy) of the same copying paper. In these copying machines, a paper refeed loop is provided to feed a copied paper again to a copying position as it is or after the paper is turned inside out. In these copying machines provided with a paper refeed loop mechanism, usually a copied paper stacking unit for temporarily storing copied paper (before the paper is fed again to a copying position via the paper refeeding loop) is provided in order to solve the problems associated with time lag between a first right side copy and a second reverse side copy or an overcopy sequence.
In the conventional electronic copying machine provided with the above-mentioned paper refeeding mechanism, however, the copied paper stacking unit is disposed horizontally within the paper refeed loop mechanism, there exists a problem such that the end of copied paper is not well aligned, thus resulting in paper jamming, double paper feeding, etc. Further, when copied papers are fed in misaligned condition, there exists another problem in that two images copied on both sides of the paper are not well matched in position or two images copied on the same side of the paper are not well aligned with each other in position.